9-propylalkylamino-5-arylaminobenzo[a]phenoxazines



Patented Nov. 7, 19 50 Moses L. Crossley; Plainfield, and Richard J. Turnet and Paul F. Dreisbach, Somerville, N. J., assignors to 'Ainerican Cyanamid Company, New York, N. Y., a corporation of Maine No Drawing. Application August 10, 1949,

Serial-No. 109,625 V This invention relates to 9-propylamino-5-ary1- aminobenzo [alphenoxazines and methods of preparing them. The compounds of the present invention in the form of. their free bases are red dyestuffs and may be represented by the following formula:

where R1 is CsHv, R2 is an alkyl group having '2 or 3 carbon atoms, and R3 is a monocyclic aro matic hydrocarbon radical, and their addition salts with acids.

In the form of their addition salts the compounds are blue dyestuffs and may be representedby the following formula:

N l a R1 I \III- NHR; Rz X 1 in which X, of course, is the anion. Other formulations have been proposed for the salts but the above formula is the one most closely in accord with the properties of the compounds.

The compounds of the invention, particularly in'the form of their bases, show extraordinarily high activity against tubercle bacilli. The very high activity appears to be specific to the propyl group, and the change in activity is not uniform with lengthening hydrocarbon chains on the" 9-amino group. The dimethylamino compounds show very low activity in mice; in many cases the activity is so low that the compound can almost be con'sidre'adas inactive;- s-dietnymmino compdunds are more v1 abfivefi :dnd the correspondin 6 Claims. (Cl. 260-244) I 2 p F. dipropyl compounds are from two to eight times as active as the diethyl compounds.- Even a single propyl group results in a great increase in activity, the ethylpropyl having an activity approximately twice as high as the corresponding diethyl compound. When butyl radicals are present on the Q-ami'no group, theacti'vity drops precipitately, the dibutylaminogroup, being no more active than the dimethyl and, for all practical purposes, can be considered asinactive. In the case of the propylbutylamino compounds, the great effect of the propyl group causes the activity to rise well above that of the dibutylamino compound, but the compound is markedly less active than the preferred dipropylamino compounds. The reason for the extraordinary effect of the propyl group, even a single propylgroup, is not fully determined, and particularly the anomalous effect which is noted with lengtheningthe hydrocarbon chain beyond propyl has as yet no explanation. It is, therefore, not desired to limit the present invention to any theory of Why the propyl group should exert so great an influence on the effectiveness of the compounds against tubercle bacilli and the butyl group such an adverse effect. It seems reasonably certain that itis not a question of fat solubility, or other lipophilic properties, because the lengthening of the hydrocarbon chain on the 9-amino group to butyl, which should increase fat solubility, destroys activity.

The aryl radical on the 5-amino group is not without efiect. The p-tolyl radical produces-a compound which is considerably more active than the phenyl or ethylphenyl radicals, but the difier ence brought about by the presence of a propyl radi'cafon the Q-amino grouostiu produces the same effect; namely, an activity which varies from two to eight times or more" that of the diethyl. Because of their high activity and relatively low production costs, the '5-"p-to1ylamino compounds constitute thepreferred species although the invention is not broadly limited theretov i The following table shows the relative average survival time of mice infected with a virulent strain of tuberculosis and treated with varying doses of 9diethylamino, 9-ethylpropylamino and 9 dipropylamino arylamino benzophenoxazines. In every case the control mice, which received no drug, died, the average survival time being about two weeks. The other groups of mice were fed the dosage of the drugs for seven days mixed with their food.

the 9-dipropylamino compounds is of the order of magnitude of eight times as great as that of the corresponding 9-diethylamino compounds. The activity of the ethylpropylamino compounds is about twice that of the diethylamino. With the less active compounds, the dipropylamino compounds are at least twice as active as the diethylamino compound.

The following table shows the survival time of TABLE I Median survival time in days for doses in mgJkgJday indicated below CgH5,C3H7.. m: 41 22 11 Q ogmhnn 'rdx c .44 1 28 T22 19 161 CEO oanmuu; .116 -49129 :21

Gin- 3- CzIfZCsHL- 41 41 31 24 'om-G- ozrmiuu. 56 1 .51 3s 3s '29 23 v on, v

@- oamtuu. 5 33 22 20 (61301 1 1 '42 4o '25 2a 19 1a I OH: 1-

: $114551 that a majority of the mice are still alive on that day.

It will be noted that with the more active-drug's in the higher, therapeutic dosesthe activity of the averagev mouse after treatment; with a ber of drugs, including: substantial1yiv inactive ben'zophenoxazines, and .therstandard'druz. stre tomvc-inw Many of the figures are repeatediirom" may beusedIand, :it,..is an advanta e. thatiitis Table possible:topreparethe compounds by a numben 7 :7 Median survival time in days for doses i I in mgJkgz/day indicated below i Y B: R; and R1 p 64,0 .-s 160 so 20 1o CILQ- 0551),.-- 152 no 49 29 21 7 27 27v 20 I his 20 19 l8- l7 (C4Ho): Toxic 34 2 19 18 Doses in mgJkgJday indicated below Streptomycin'ktij. s- Q Toxic 42 30 23: [35,...

1 Treatment for 14 days instead of 7, administration subcutaneous instead oi oral.

, While relative activity comparisons, are useful in.bringing out the similarityin thegefiectofthe propyl group, the actualvalue of any drug-is .de-. terminedby the. results obtainable with the maximum dose tolerated by..the ..test subject. Here the advantages of the 9 -dipropylamino compounds, and particularly the preferred compound, 9-dipropylamino 5 p-tolylaminobenzophenoxazine, are brought out most strikingly and are also illustrated by Tables I and II, giving survival time of a majority of tested mice with various drugs. As statediabovethe-controls all die, the average being inabout two weeks.

TableII shows that a majority (it the. mice survive a little longer when fed thejglimethylamino compounds. The survival time of' the average mouse increases to'about 42 days fors'treptomycin, the most common and efi'ectivedrug now in use against human tuberculosis. 'llhe -9-diethyl'- amino-5-p-tolylaminobenzophenoxazine gives a survival-time of a'littleover 60 days. The corresponding dipropylcompound in a dose comparable to the maximumtolerated dose for streptomycin-gives. an average survivalof greater than days. In view-of .the fact the life span of a mouse is onlyeabout one-thirtieth that of man, there appears to be a fair} possibility that some of the mice that receive the optimum dose of the preferred 9 di-propylamino-fi-p-tolyl aminobenzophenoxazine:may actually be cured; something that has never occurred before with mice subjected to the extremelyfflrastictest.

It should be noted that whereas the mice receiving streptomycin were given the drug for fourteen days afterinfection, those receiving the preferred drug of the present invention received .it 'withtheir food for only sevefi days. p

Theefiectiveness of a .drugjdepends not .only on its activity but also on. its toxicity, and the tendency to develop drug-resistantstrains of micro-organisms. Inthe case of the preferred compound of .the present invention, the activity is much greaterv than thatof'jstreptomycinj the acute toxicity is much less; and bacteriological tests have, up to the present, shown no tendency to develop resistant strains of tubercle bacilli,

which is such a marked drawback with streptomycin therapy.

The compounds of the present invention may be prepared in various ways the invention includi'ng-thecompounds regardless oi the process 5 rrocesses. One syntheses involves the reac tion presid-dipropyl rninoenitrosophenol with an N=ary1;..substituted. .naph hyl amine. Ano hermethodrinvolves the, production of the 9-dipropyle aminobencophenoxazonium salt and its reaction with -.the correspo .ng 1mononuclear arylamine. whichtattaches;itself through the. aminocroup to the: 5lcarbonatom .of the benzophenoxazoniuin nucleus. ,This. latter. method- .more. flexible. in.

preparing a number of the compounds. present invention andis preferred.

As far as the ring closure step is concerned, the twoprocesses are very similar. They involve-the ring closure of :compounds containing at least one nitroso and hydroxy group, the only difference being that in the first process the nitroso 'group is on one intermediate and the hydroxy on the eta-tho other, and in the second process they are on the 7 finely-divided form in conjunction with food,

.Theinvention will be described inelreater d tan. in njuncti n. with the f llowing sp cific exampl s. .A pa t are by We ght- 9-di 'n-propylaminobenzo[alphenoxaeonium a V .v p ,l A mixture of 144 parts of 2-naphthol, 82 par'ts of zinc chloride aridglOOOparts of ethyl alcohol is heatedto the reflux temperature. To the boiling solution, 242.5 parts of N,N-di-n-propyl-4- nitrosoaniline hydrochloride are added in small F portions. Heating of'the mixture to the boiling 0 temperature is continued until no yellow run is detected from a drop of, the solution placed on wet filter paper. After cooling, the 9-di-n-propylaminobenzo[alphenoxazonium chloride zinc chloridedbuble salt which precipitates is removed 2 by filtrationand dissolved in'18,000parts"of'hot The administration may advantageously be inya.

aazmsea benzoEalphenoxazonium nitrate which precipitates is removed, yielding, after drying at 50 C.,

112 parts of product in the form of greenish plates;

with a coppery metallic luster.

EXAMPLE 2 Q-ethylpropylamz'nobenzoial phenowazonium nitrate V This product is prepared in a manner similar to that described under Example 1, except that,

228.5 parts of N-ethyl-N-n-propyl-4-nitrosoani-J.f line hydrochloride are used instead of the 242.5. parts of N,N-di-n-propyl-4-nitrosoaniline hydrochloride. I

The N-ethyl-N-n-propyl-e-nitrosoaniline' hy drochloride required here is prepared by adding gradually a solution of 166 parts of sodium nitrite in 300 parts of water to a cooled solution of 326 parts of N-ethyl-N-n-propylaniline in 600 parts of concentrated hydrochloric acid and 800 parts of water. After the reaction is complete, an excess'of'caustic soda summon is added which causes the precipitation of the mt'ro's'o base in" the 'form of :a: green oil which is finally taken up in ethe'r 56mm;- After drying this ethersolution, treat m'entwithgaseous hydrogen chloride caus es the precipitation of thehydrochloride of N'-ethyl N- n-propyl 4-mtros'oaniline which "after removal by filtration' is purified by recrystallization from hot ethyl-alcohol,- giving a yellow-greensolid' crystallifie' material: I

: "'-phe nylatzi no-Q-di-n pmpQiaminobenzoKal phenorazom'um nitrate 2 N03 mixture 1519? parts" of 9-'di-n-propylam inobenzolalphenoxa'zoniuin nitrate; prepared {aclco din to Exam e-11 p rt o nilineri 1500 parts of ethyl alcohol is warmed until 'coin plete solution ,results. The solutionis allowed toilc'oolpanq stand until precipitation of bright green needles is substantially. complete. The precipitate is then separated by filtration and re-'. crystallized from ethyl alcohol. The productis obtainedin the form of the monohydrate.

The product isdissolved in acidified; ethyl jalc'ohol, producing an intensely-colored greenish;- blue solution having a maximurnli'gh't absorp tion at a wavelength- 0f approximately 660 mp. 1?. add ti vo L- h s lut on n ,v red, showing a maximumabsorption at 531 m and constitutes the freebase. V

'5'" 4: iben'zololphenoxazonium nitrate Watefl -Atftr larification of theresulting s'olu-,:: Q50 partswr concentratednitric-acid are": added: Upon cooling; the 9-di' n-propylaminoe;

The proc'eduremf Example followe'drbut: the ""-'ar1iline' ';is replaced with '1160'1 partsti of,, .p-: toluidine. The precipitate obtained consistSziEof brownish-greefifinedlsland is in the form of the 5 1 hemihydrate. v v On dissolving the green needles in acidified ethyl alcohol, a blue solution is obtained. which turns to the red'of the free base when made alkaline with ammonium hydroxide. The absorption maxirna of the blue and red solutions are at substantially the same wavelengths as in the case of the product of Example 3. 7

EXAMPLE-5w Ir J, 5- 4 ethy ZplrenyZamin'o) 9-di-1i-propylamino- 'j' benzola lphenoxazom'um nitrate 0/ IMHO-0111 N x v ,:;FIhe procedure of Example 3 is followed; subs t s-d 16 pa ,Of 't'm 'uidine 0 the 140 a ts o n linez; Thero uct i o a e i m talline f rmflasbr wnvne dles, wh h ve .blu solut n c acidified eth l alcoh l hane neuto r dzontheladditi nroiamm n u hy oxi e '5-'(z methylph'efiyldmino3'-9fdi-n-propyl i-ne 1 ow r' p e ins t e-a. Ma ts"q io i n The pr'oduc ,j ihe fo m b h f needles I The-product shows "the same 0101: ha g? i s ll fi l .i e 0, QXVCQ'D'G ha in the form f "the" 'saltthe solutionis' a distinct p heiz EIF Q iQ H .i i 5- 2Adimethylphenylcmiho9dim-prowl ammopgeng r iphenqwaeo i tr t aminoberizolal'lph'efnordeoaiuninitrate standing a precipitate for njsfwhich is recovered masses :fiche-procedure:otxExample ls'iifdllowed replacing the aniline with 182 .parts1offI2;4-xylidine; The initials reactionuproceeds somewhat =-.more rapidly than in the casezofz Examplei ii"; but the precipitation of the. crystalline product is some- IEXAMPLEQ/ I 5 -(4- isopropylphenylamino) ll-di-n propyle j ominobenaolhlfimeg oxazonium nitrate" Q,

in' the preceding examples.

5- (st-methylphenylamino) -9-ethylp1'opylaminobenzo [all phenoxaaonium nitrate 3'5 C H I IOs A solution of 133 parts 'o'fthe product of Example 2is dissolved in--l,'000 parts of ethyl al- "cohol and 112 parts of p-toluid-in'e addedwith stirring. lhecolor of -the solution changes from a red-blue to a green-blue, and on cooling and p 7 by"filtratioh: After re'-crystalli zation from ethyl alcohol, the produetiisrobtained.- as-;a purple solid, soluble n ethyl alcohol to. give a blue solution under cid conditions, 'whlch solution turns 'to its?? assesmmoni EQ "s' 'ptttaaaali ahtimyzmaobeaaraphenoxazonium nitrate The procedure of Example 10 is followed, replacing the p-toluidine with 98 parts of aniline. The product recovered is in the form of green crystals with a metallic luster. Like the products or the preceding examples, it dissolves in alcohol, giving a blue solution under acid conditions,

which turns to red on the addition of alkali.

1D? EXAMPLE 12* phenylaminowedi n promilaminobenlzota]Ijj -1 phenomazine base (emai 369 parts of n-propyl'bromide are added to a slurry'oit 2l8 ipartsofrmaminophenolin 300-parts of ethyl alcohol. Thereaction mixture is then heated under a gentle reflux until the reaction is complete Alcohol and-some"unchanged'propyl promise arei-emoved' by distillation, and the residue poured into water and treated with sodi um carbonate -to separate: the aminophenol' deriva i t-ives'. Anoil layer and a water layer are formed; the former being-taken up in et'her, and the ether removed by distillation. The residue is added-to the alcohol and unchanged propyl bromide recovered from the original reaction mixture, togetherjwith'an additional 123 parts of fresh propyl bromide". "The solution is'then refluxed until reaction appears complete and, finally, the alcohol and a small amount of unchanged propyl bromide are removed by distillation.

The product obtainedis poured into 1,000 parts of water and the mixture made alkaline by adding solid soda A water-insoluble oil is produced which isremoyedby' decantationand purified by vacuum distillation. It is a straw-colored, viscous liquid, which turns deep red on exposure to air. The product isthen dissolved in 880 parts of oncentra'ted hydrochloric acid, and'l03 parts olf 'ssodiu'm nitrite in 210 parts of water is added gradually .to' the solution, the temp erature'j being mainta'ined'below110C. An orange-colored solid form's afte'r't'he reaction is complete and is' rcmovedby filtration', washed with dilute hydro-' chloric acid and dried., The or angel; colored "2 nitroso-5 din-prl1l)yl amino phenol is added to a solution of 169' parts of N-phenylnaphthylamine in 11500 parts ofethyl alcohol, acidified with a little hydrochloric acid. The mixture is stirred and heated under reflux until the reaction is complete, an intensely bluecolored solution being-obtained. The solution is diluted with an equal volume of ethyl alcohol and treated with an excess-of concentrated ammonium hydroxide, which precipitates a slightly oily product soon solidifying to the dark greenishcol ored base? This is: removed by filtration and dciedito azgreenishzpowdert- .1 Y The base dissolves in alcohol to form a purplish solution which can be transformed into a greenish-blue solution by the addition of hydrochloric acid. Ether is then added and the solid hydrochloride of the free base precipitated, filtered and recovered.

EXAMPLE 13 .5- (4-methylphenylamino) -9-di-n-propylaminobenzomlphenoacazine base znasgsoa A slurry of 25;: IpartsII-O1l5:(4-methy1pheny1- amino) 9. 7 :11 in -4 propylaminobenzophenoxazoniuirii'iitrate; preparedas" described in Example 4, is slurried in 200 parts of'ethyl'al'cohol and treated r: 7 atoms; and 3Rai is a :Vbenzne oradidar "andzitfieir addition-saltsMith-acidsJ; 11g 32. -As ainewi chemical'zcompo'u'nd; he base new 'from a greenish-blue to a brownish red. The

' h r o ns N-n-nr s p lan 20 7 ing the fo11dwing;--f.ormu1a=:. with 10 parts of concentrated aqueous ammonium 5 -5 :.v hydroxide. The color of the mixture changes latter, which is thebase, is insoluble and is col- 7 lected and washed with water; thereupon it is dried and Constitutes a greenish-black powder 10 which melts at about 178-179" C. /N-

EXAMPLE 14 11 31 2. H N l I Z' 0 Z minobe hzom Q A s 1.

9 2 9 18 p fiz g; 1p o salts of the base of claim 2 with strong mineral acids.

4. As a new chemical compound, the base having the formula:

l n -propy1 -N-isopropy1 4 -.nitrosoani 1ine I is Pre ar b .f llq l t e pr ed e Q Examp ziirenlacine t e N y1- -;n-p py1a i1 wit ii e.-.,;1'he product is then transformed into the I beno p he a n um n t a e b t e process or N Examp e 1,. o 1 a pmcgalqm f y h P m/ is0p1'opyl-a "1 :omomom/ f5- "A w eh ali" i ipoii i th bii salts of the base or claim iwi'thfstrong mineral a ds-z 'i g 6. "As-a new chemical compound thebase ha'y aminob'eneo a] phenoara z o'ri um nitrate Y r cmomoni f fljhev process of Example 3 is carried out, substituting the product of Example 14 for the 9'-di- CHaCHaCHz 'n' ropylamino compound used in theexample.

a rodiiot is obtained which dissolves in alcohol, MOSES L; CROSSLEY.

eiy n a-ib solution d r acid conditions and R J. T

ag ee solution under alkalinecondition's. o PAUL" DREISBACH.

V As new chemical compounds,"the compounds v a BE ERENQ- YSE FE I leei from the class consisting of the bases The fofiowirig -references are ofrecord in'the i file..= I-.-t. D nfia.

ay' g the formula:

ini whighQRiis Cal-I7, R2 an aikyi grioupiiaviii more than one and not more; than three carbon July 1923 

1. AS NEW CHEMICAL COMPOUNDS, THE COMPOUNDS SELECTED FROM THE CLASS CONSISTING OF THE BASES HAVING THE FORMULA: 